Chapter 21 - Section 21.3 - General Aspects of Adaptive Immunity - Apply What You Know - Page 827: 1

Clonal deletion is a process that occurs in the development of immune cells, specifically T cells and B cells, to ensure self-tolerance and prevent the immune system from attacking the body's own tissues. During clonal deletion, immune cells that would recognize and react against self-antigens are eliminated to avoid potential autoimmune reactions. Clonal deletion is a case of apoptosis, not necrosis. Here's why: **Apoptosis:** - Apoptosis is a controlled and programmed form of cell death. - It is a natural process that occurs during development, tissue maintenance, and the immune response. - Apoptosis involves a series of cellular events that lead to cell shrinkage, nuclear fragmentation, and the formation of apoptotic bodies. These apoptotic bodies are quickly engulfed and digested by neighboring cells or phagocytes, preventing inflammation and damage to surrounding tissues. **Necrosis:** - Necrosis is a form of cell death that is typically caused by external factors such as injury, infection, or lack of blood supply. - Necrotic cell death is often associated with cell swelling, rupture, and the release of cellular contents into the extracellular space. This can trigger inflammation and damage nearby tissues. In the context of clonal deletion, the immune cells that are targeted for elimination undergo apoptosis. This programmed cell death prevents the release of potentially harmful self-reactive immune cells into the bloodstream, minimizing the risk of autoimmune reactions. The controlled and non-inflammatory nature of apoptosis is essential in this process, as it prevents the immune system from generating an inappropriate immune response against the body's own tissues.

Clonal deletion is a process that occurs in the development of immune cells, specifically T cells and B cells, to ensure self-tolerance and prevent the immune system from attacking the body's own tissues. During clonal deletion, immune cells that would recognize and react against self-antigens are eliminated to avoid potential autoimmune reactions. Clonal deletion is a case of apoptosis, not necrosis. Here's why: **Apoptosis:** - Apoptosis is a controlled and programmed form of cell death. - It is a natural process that occurs during development, tissue maintenance, and the immune response. - Apoptosis involves a series of cellular events that lead to cell shrinkage, nuclear fragmentation, and the formation of apoptotic bodies. These apoptotic bodies are quickly engulfed and digested by neighboring cells or phagocytes, preventing inflammation and damage to surrounding tissues. **Necrosis:** - Necrosis is a form of cell death that is typically caused by external factors such as injury, infection, or lack of blood supply. - Necrotic cell death is often associated with cell swelling, rupture, and the release of cellular contents into the extracellular space. This can trigger inflammation and damage nearby tissues. In the context of clonal deletion, the immune cells that are targeted for elimination undergo apoptosis. This programmed cell death prevents the release of potentially harmful self-reactive immune cells into the bloodstream, minimizing the risk of autoimmune reactions. The controlled and non-inflammatory nature of apoptosis is essential in this process, as it prevents the immune system from generating an inappropriate immune response against the body's own tissues.